In the anime

In the main series

Noivern's body becomes surrounded in a thin light-blue aura, the inside of its ears glow light blue and then blue static appears on both sides of its ears. Noivern then sends a swirly supersonic wave of light blue aura towards the opponent, which becomes straight as it is about to hit the opponent. Or Noivern's ears glow white and it then fires a blast of powerful white sound waves from them at the opponent or the inside of Noivern's ears glow white and a ball of white light appears in front of its ears and a blast of powerful sound waves comes out from the white ball and heads towards the opponent.